It also increases the animosity between Sergeants (for plucking a good Runner out from under them), and adds risk to promoting a well-mannered Runner that doesn't have the combat training to survive as a Trooper.
To the original post, I think what makes a good Byn Sergeant is coming up with ways (like this) to make your Stripes feel like a part of something. Make all that training -worth- something to them. Engender trust in your leadership, take on both the boring and the bombastic. You're not just a Bynner. You're not just some Raging Tembo. You're RIEV'S Raging Tembos. And when he eventually dies so that his troopers may live, it will be VESELEKA'S Raging Tembos, carrying on tradition, etc.
I should make another Byn Sergeant.
There's some good ideas in this thread (not the least of which is Riev making another Byn Sergeant

).
When the units were introduced to the Byn, nothing really changed. Members of different units would still mix together for any Byn purpose and activity as was before. This was because while the units probably should be doing things like training, contracts, etc within their own units, in practice there simply isn't enough player population to support such segregation. The only time that the units really mattered was when the Byn was actually physically separated into southern and northern branches, and the units (and their Sergeants) would be more or less permanently stationed in one city or the other. Whenever the Byn was reconsolidated (due to not having enough players), that would disappear and everyone would get mushed together again, and that's now a essentially permanent now that Tuluk is off-limits to play.
Anyway, that's not to say that the units were a bad idea, but I agree the concept could do with some tweaking.
I like the general pool idea, for one. Taking that further and meshing it with Riev's idea, you could have all Bynners, Sergeants and below default to a general pool (ie. everyone's just part of the PC Warband), and only award a unit to a Sergeant once they've earned it in the eyes of their Lieutenant. If there are multiple active Sergeants, they could fight for the right to lead the prestigious unit, or the right to imprint their own name for a relatively unknown or forgotten unit. Heck, maybe even cut the named units down to only one available to lead, so that it creates an artificial bottleneck for Sergeants (and the Bynners loyal to them) to fight over. Those who make it into the named unit might be considered a cut above. This way, things mesh with the IC/OOC realities of the current Byn - everyone's playing together already anyway, and the separate units don't make much difference at all. Once someone gets into one of/the elite unit, then they can be looked up to and tread upon the rest of the regular grunts.
Alternately, you could just create a separate elite unit, and keep the regular units, but I feel that in practice it'd be easier for everyone to just look up to the one named unit (including outsiders, who might not know otherwise, but if they see that a Bynner has a unit patch, all of a sudden they're special if no other Bynners have one). Having one named unit would also allow everyone to keep track of who were the famed leaders/members of same a bit easier as well. With so many units it's hard to remember who led which. Then, it really could be Veselka's Raging Tembos, and maybe the Tembos could even be retired if a new incoming Sergeant earned the right. The new Sergeant could either take over and continue with the Tembos in Veselka's tradition, or start up their own new elite unit (using the other unused patch, or encouraged to write up their own, etc).
There was also an idea for a time by some of the clan imms to create further differentiation/progression using pins or something that one would attach to the patches, but I don't believe that really went anywhere.
Anyhow, we're getting a bit off topic - but IMO, what makes a good Byn Sergeant isn't much different than what makes any good PC leader: consistent RP of their character, a willingness to involve and create for those they lead, and the ability to make the game world come alive for those around them (especially to portray the grittiness of the Byn).